3Com LANPLEX 2500 Operation Manual page 126

2 O G
PERATION LOSSARY
backplane
In the LANplex system, the "motherboard" that performs various logic and
control functions. Located in the back of the chassis, it supports three
100Mbps FDDI paths, three 4 or 16 Mbps token ring paths, three 10Mbps
Ethernet paths, and a VMEbus.
B port
In FDDI technology, each DAS contains two ports: A and B. The B port is
connected to the incoming fiber of the secondary ring and to the outgoing
fiber of the primary ring. A properly formed trunk ring is composed of a set
of stations with the A port of one station connected to the B port of the
neighboring station. See also A port.
B to M link
One of several detailed connection rules for a specific port relative to other
ports. The B to M (master) port rule is a tree connection with possible
redundancy. With this link, a station must not go to THRU state in
Configuration Management (CFM). Port B on one station has precedence for
connecting to an M port on a different station (single MAC station).
bridge
Equipment that connects LANs, allowing communication between devices
on separate LANs. Bridges are protocol independent but hardware specific,
with communication limited to the data link layer and physical layer of the
ISO reference model. Bridges connect LANs that have different
hardware and use different protocols. Examples: a bridge that connects
an Ethernet network to an FDDI network allows the two
networks to send signals to each other. The LANplex 2500 Ethernet/FDDI
Switching Module (EFSM) can operate as a translation/transparent 802.1d
bridge. See also Spanning Tree Protocol.
BUS
Broadcast and Unknown Server. The set of functions implemented in an
ATM network that provides LAN-to-LAN transmission support while a LAN
connection is being established. The BUS also supports Ethernet Broadcasts
Mode by sending broadcast data to all LECs.
broadcast packet
A single packet that is sent to all stations in a network. See also multicast
packet.
broadcast/multicast
The network congestion that results when many stations, responding to a
storm
transmission by one station, transmit a large number of frames. This
condition can overstress a network and cause end-stations to stop
responding or fail.